Compressor



- 1,466,974 S. H. TODD COMPRESSOR Sept. 4, 1923.

Filed March 18. 1921 Patented Sept. 4, W23.

BEL H. TODD, OF DETROIT, MICHIGAN.

COMPRESSOR.

Application filed March 18, 1921. Serial I la. 453,485

To (ZZZ whom, it may concern:

Be it known that .I, S UEnAH. Tno, a citizen of the Uhited States,residing at Detroit, in the county ofWayne and State of Michigan, haveinvented certain new and useful Improvements in Compresors, of

very high volumetric efiiciency, which will start easily under load, andin which lubrication of the moving parts can be efiected without dangerof the lubricant becoming entrained in the gas; while further objectsand advantages of the invention will become apparent as the descriptionproceeds.

in the drawings accompanying and forming at art of this application Ihave shown one em nliment of my invention although it will be understoodthat this drawing is intended merely for illustrative purposes and doesnot restrict me to an 1 of the constructions therein shown. Fig. 1 is avertical, longitudinal, sectional view showing my improvements asapplied to a two-cylinder myself thereto. The sleeves are spaced fromcompressor; Fig. 2 is a vertical sectional view corresponding to theline 2-2 of Fig. 2 and looking in the direction of the arrows; Fig. 3 isa vertical longitudinal sectional view of one of the pistons drawnto-Ylenlarged detail; Fig. is a view of the same piston taken at rightangles to Fig. 3 and showing the same half in section and half inelevation; and Fig. 5 is a sectional view corresponding to the brokenline 5-5 of Fig. 3.

Describing the parts by reference characters, 1 represe ts the shell orbody of my improved compressor having at its lower end a crank case 1having therein the usual crank shaft 2 and having at its upper end ahollow cylinder block 3 formed at its upper and lower ends with internalflanges 4. and,

5. These flanges are formed with circular seats snugly receiving thesleeves 6-6 which constitute the cylinders. I have shown a two-cylindercompressor since this is the simplest balanced form, but I do notrestrict thewalls of the cylinder block so as to form, in conjunctionwith the flanges 4, 5, an annular chamber surrounding each cylinder.

The crank case is completely closed excepting for the removable plate 1which is hermetically secured thereto, and for one or more restrictedopenings 8 which lead to the chamber 7.

The upper end of the cylinder block is faced as at 10 for the receptionof a closure plate 11 in which are mounted the outlet valves 12-12 whichmay be of any suitable or desired construction, the whole beingsurinounted by a hollow cap 13 in which is formed the compressor outlet14. The side of the cylinder block is formed w'ith the compressor inlet15, which, in the case ofre 'frigemting pparatus is connected h theexpansion coil (not shown).

The pistons consist of hollow cylindrical bodies having bearing surfaces16,- 17' 'at their ends and one or more longitudinal tions. The portion16 is grooved for the re- .recesses 18, 18between suchbearing'p'orception of rings 19 and the length 'of the I recess is atleast as great as and preferably somewhat greater than the length of thestroke. The sleeve 6 is formed with a port 20 registering with eachrecess and so located as always to register and communicate therewith,whatever be the position of the piston. In the present embodiment theserecesses are longer on those sides of the piston through which areformed the apertures 21 for the wrist-pins, and throughout the re-.mainder of the piston are of reduced extent .as shown at 18 ,'in orderthat the bearing surface of the piston may be as great as possible,although this is primarily a matter of design. Communicating with theupper end of each of the recesses 18 isa longitudinal passage-way 25,formed one at each side of the piston axis, and carried by the pistonhead is a leaf-spring 26 which overlaps both of said passage-ways insuch wise as to form a flap valve. In the present embodiment this springis held in place by a screw 27 located at the center of the piston head,and the lower face of the cylinder head-closdreflfl is channeled asshown at 28 for the reoepti n of said spring.

As a consequence of my improved construction, the inlet ports orpassageways 25 of the piston are always in 00131111111103,-

tion with the ports 20 of the cylinder s6 that time but gas movement andpiston movement occur together. Also the proximity of the chamber 7 andports 20 causes the immediate presence of an ample supply of gas to fillthe cylinder. I prefer to have the recesses 1 8 as long as the strokeplus the width of the port 20 although it is permissible to cover aportion .of such port at each end of the stroke. thus slightlydecreasing the length of the recess. It is important, however, that noportion of the piston rings be dragged across such ports by reason ofthe wearing'effect produced thereby, and it is also of importance tokeep the ports 20 always in communication with the passageways in orderthat the inlet of the gas (or air) to the cylinder maycommenceimmediately upon the beginning of the down stroke without theproduction of any pronounced vacuum.

-For lubricating the crank and pitmans the splash systemispreterably-employed, and the arrangement here shown provides for thecomplete and successful lubrication of the parts without danger of theadmission of oil to the compressed gas. This is particularly useful inconnection with refrigeratim; apparatus for the following reason.

During the existence of any extended idle period the lubricant in thecrank is liable to become considerably saturated with condensedrefrigerant, and upon starting-theapparatus the sudden local decrease ofpresmeagre sure causes a pronounced frothing of the lubricant. Thenarrowness of communication between the crank case and the rest of thecompressor prevents the entrance of any large quantity of this frothinto the chamber, while the formation of such chamber prevents entirelythe admission into the cylinder ports of any oil which may thus enterthe lower end thereof.

Experience shows that this compressor can be operated more cheaply andefiiciently than any other heretofore known, but I do not limit myselfto any specific details of construction except as recited in the claimsannexed since many changes can be made without departure from myinvention.

Having thus described my invention, what I claim is:

In a compressor, the'combi'nation with a cylinder having an inlet spacein the wall thereof and a port from said space into the interior of thecylinder, of a piston in the cylinder, said piston having an externalannular recess around the same registerin at all times with said port,passages exten in upwardly and inwardly from the upper en of said recessand opening thru the top of the piston, and a flap valve fastened'to thetop of the piston and controlling said openm s.

n testimonywhereof, I hereunto affix my signature.

SAMUEL H. TODD.

